My Blazer has no heat. It just blows cool air no matter how long it's been running. The motor gets warm, so do the hoses to the heater. But, my temp gauge only reads 100deg when running and maybe 150deg after you turn it off. It has an aftermarket 350 and runs like it's supposed to. So I am going to flush the heater core out but wondered if it could be something else? I already flushed out the radiator and block, and changed out the tstat (195deg).

 

if both hoses going to the heatercore are hot then it may be a blend door issue. i just worked on a ford that wasnt getting any heat, it had one hot hose to the heatercore and the other was barely worm, i flushed it out and it worked fine, im think it just had a air pocket in it cause when i pulled the lines off no water came out.

 

That's maybe what's wrong with mine. Now that you mention it. one hose was hot and the other wasn't as hot, it was just really warm. But they were not the same temp. I'm going to flush those hoses and the heater core out tomorrow, thanks! now to just figure out why the temp gauge only reads 100deg when running. Any thoughts?

 

thermostat stuck wide open? or bad temp gauge. if your thermostat is stuck wide open the water isnt staying in the engine long enough for it to heat up to make heat

 

Make sure it's 50/50 mix....

 

So...I figured it out! I should take pics, but the two heater hoses were in the wrong places! One was going to the water pump (correct) but the other one was going to the radiator (incorrect). I put that one to the intake manifold and problem solved! The thing heats up perfectly! It's running great now.

 

Watch out and make sure the heater core isn't leaking. Pretty common for idiots to bypass them instead of fixing it when they selling a truck.

 

It's not. I'm sure of that. I have awesome heat now and everything is hooked up the right way.

 

One hose was from the intake and I changed mine today from the radiator to the water pump, sure blows hot air now.